All businesses reserve the right to "refuse service to any customer" and because of this rule they can ban you from playing at their Casino. And you can't do anything about it.
No, you can do a lot of things about it. First of all you can boycott them and say every gambler you know not to play at their casino.
You know customer is always right.
That won't help you get unbanned, Casinos have their own rules, and Card Counting is not allowed (it's not even effective anymore because they use more then one deck) so it is pointless anyway and you can cry like a bitch about it all you want but it will have no affect on Casino or it's accountability because what you're yelling about is considered cheating and others will view this as just a sad attempt to defame a Casino.
And 'no' customer is not always right.
Only fudsters think that they can say anything about a business and make it sound real but people are not fools, they will weigh both sides of the argument and make their decision accordingly.